Focal plane arrays (FPAs) are two-dimensional arrays of photodetectors disposed in the focal plane of a lens for applications such as imaging, spectrometry, lidar, and wave-front sensing. Conventional FPAs typically provide analog readout, with the analog signals generated at the pixel level converted to digital signals by analog-to-digital converters (ADCs) that are external to the FPA. The converted signals can then be processed according to the demands of a particular application. Specific analog designs can target, and possibly achieve, one or more design requirements, but fail when simultaneously targeting the most aggressive design parameters for imaging applications, such as transient target imaging and wide-area surveillance.
Wide-area imaging with commercial off-the-shelf (COTS) FPA detectors trade frame rate for spatial resolution. As a result, fast moving targets are recorded as streaks moving across a field-of-view. These two-dimensional (2D) streaked images lack temporal history and provide degraded spatial images. Conventional digital-pixel focal plane arrays (“DFPAs”) have on-chip global capability for single transient-feature extraction in a snapshot, but are not capable of multi-target and multi-frequency discrimination. Persistent and wide-area surveillance applications can therefore benefit from techniques that enable search and track of fleeting targets while maintaining a wide field-of-view.